Development of pelleted feed containing probiotic Lactobacillus rhamnosus GG and Jerusalem artichoke for Nile Tilapia and its biocompatibility studies

Abstract

Growth performance and immune systems of tilapias could be improved by Lactobacillus rhamnosus GG (LGG) and Jerusalem artichoke. This research aimed to determine the effects of Jerusalem artichoke on LGG viability after drying and pelleting and their subsequent exposure to simulated gastrointestinal conditions. Fresh LGG cells were added into wall material solutions, including alginate (AL), alginate + milk powder (AM), and alginate + milk powder + Jerusalem artichoke at different concentrations (AMJ). The solutions were then spray dried to obtain LGG powders. The powder with the highest cell number was then selected to mix with tilapia feed mash and pelleted using a nonthermal feed extruder to obtain pelleted feed containing LGG and Jerusalem artichoke. The LGG viability spray dried powders and pelleted feed were analyzed for their cell counts after drying and after exposure to simulated gastrointestinal conditions. The result showed that the number of viable cells in AMJ was significantly higher than AM and AL after drying. The number of viable cells under both simulated gastric and bile salt fluids was improved with the increasing of Jerusalem artichoke concentrations. The number of viable cells after pelleting process could be maintained. LGG in the pelleted feed could also survive under the simulated gastric and bile salt conditions. The study indicates that JA enhanced LGG viability after drying and exposure to simulated gastrointestinal conditions. The pelleted feed containing LGG and Jerusalem artichoke could be applied in tilapia farming, providing convenience to the farmers, and valuable effects to the fish.

Keywords: Encapsulation; Fish; Prebiotics; Probiotics; Viability.

Fig. 1

Viability of LGG powders before and after spray drying; AL LGG powder with only alginate, AM LGG powder with alginate and milk powder, AMJ10, AMJ15, and AMJ20 LGG powder with alginate, milk powder, and JA at 100, 150, and 200 g/L, respectively. ^a–bMeans ± standard deviation with different letters were significantly different (P ≤ 0.05)

Fig. 2

Viability of LGG powders in simulated gastric fluids (pH 1.5 (A), pH 2.0 (B), and pH 3.0 (C)); AL LGG powder with only alginate, AM LGG powder with alginate and milk powder, AMJ10, AMJ15, and AMJ20 LGG powder with alginate, milk powder, and JA at 100, 150, and 200 g/L, respectively

Fig. 3

Survival rates of LGG powders after incubating in low pH conditions for 2 h; AL LGG powders with only alginate, AM LGG powder with alginate and milk powder, AMJ10, AMJ15, and AMJ20 LGG powder with alginate, milk powder, and JA at 100, 150, and 200 g/L respectively. ^a–cMeans ± standard deviation with different letter within the same color was significantly different (P ≤ 0.05). ^A,BMeans ± standard deviation with different letters within the same pH was significantly different (P ≤ 0.05)

Fig. 4

Viability of LGG powders in bile salt conditions (bile salt 3 mL/10 mL (A), bile salt 5 mL/100 mL (B), and bile salt 10 mL/100 mL (C)); AL LGG powder with only alginate, AM LGG powder with alginate and milk powder, AMJ10, AMJ15, and AMJ20 LGG powder with alginate, milk powder, and JA at 100, 150, and 200 g/L, respectively

Fig. 5

Survival rates of LGG powders after incubating in bile salt conditions for 3 h; AL LGG powder with only alginate, AM LGG powder with alginate and milk powder, AMJ10, AMJ15, and AMJ20 LGG powder with alginate, milk powder, and JA at 100, 150, and 200 g/L respectively. ^a–cMeans ± standard deviation with different letter within the same color was significantly different (P ≤ 0.05). ^A,BMeans ± standard deviation with different letters within the same pH was significantly different (P ≤ 0.05)

Fig. 6

Viability of LGG in Nile tilapia pelleted feeds during exposure to simulated gastrointestinal condition; Fresh cell LGG grown in MRS broth for 24 h, AMJ20 LGG powder with alginate, milk powder, and JA at 200 g/L, PLF pelleted feed containing LGG